function out = GeoSum(InSeries, K)

T = length(InSeries(:,1));
N = length(InSeries(1,:));
T = T-K+1;

out = zeros(T,N);

for jt = 1:T
   
    out(jt,:) = 1;
    for jk = 1:K
       out(jt,:) = out(jt,:) .* InSeries(jt+jk-1,:); 
    end
    
end
